If you took the initial approach in using this service as a training mechanism ... incorporating phone training at the same time, it may not be perceived as so intrusive. I think it's great!
Doing it right would be to have someone like Jerry mystery shop, bring him in to train and coach based on his findings, then monitor with this service for optimal results. Be honest with your sales staff and let them know that you will be spot checking on a regular basis. Add the word "CONSISTENCY" to your mission. Some people won't like it, but it is a business. And their success is linked to the success of the dealership. How do you argue with that without coming off as an arrogant and selfish butt-hole?